code: def test_adding_timeout_twice(self) -> None:
      with LoopAndGroup() as ctx:
          func = _make_invocation_counter(ctx.io_loop, stop_after=2)
          ctx.group.add_timeout_callback(
              callback=func,
              timeout_milliseconds=1,
              callback_id=make_id(),
          )
          ctx.group.add_timeout_callback(
              callback=func,
              timeout_milliseconds=2,
              callback_id=make_id(),
          )
      assert 2 == func.count()
  
imports: from __future__ import annotations
  import pytest
  from concurrent.futures import ThreadPoolExecutor
  from itertools import repeat
  from tornado.ioloop import IOLoop
  from bokeh.util.serialization import make_id
  from bokeh.util.tornado import _CallbackGroup
label_desc: Use image node_id 9 for calling the TestCallbackGroup obj's underlying member method code with example usage: obj.test_adding_timeout_twice() without return types